Ignition device for a gas fired appliance

ABSTRACT

Spark generation means for igniting a gas flame, one of the contacts of the spark generator contact set being mounted on a bimetallic element to hold the contacts open when the bimetallic element is heated.

United States Patent 1191 5/1967 Takahashi ..317/93 Branche 1 Feb. 27, 1973 s41 IGNITION DEVICE FOR A GAS FIRED 3,539,283 11/1970 APPLIANCE 1,982,561 11 1934 [75] Inventor: William H. Branche, Indianapolis, 2,960,158 11/1960 [73] Assignee: Carrier Corporation, Syracuse, N.Y. 310791984 3/1963 3,582,249 6/1971 [22] Flled: July 28, I971 [21] pp No 166 893 FOREIGN PATENTS OR APPLICATIONS I 1,091,496 10/1954 France ..43l/74 52 U.S.Cl.' ..3l7 93 317 97 431 68, i 1 Primary Examiner-VOIOdynlyt Y. Mayewsky 511 1111. c1. 1 23;; 3/00 may-Harry Mam", [58] Field of Search ..3l7/82,.79, 96, 9 2, 97, 93;

431/256-257, 264, 46, 68, 74, 78 ABSTRACT I Spark generation means for igniting a gas flame, one [56] ,Rehrences m of the contacts of the spark generator contact set UNITED STATES PATENTS being mounted on a bimetallic element to hold the contacts open when the bimetallic element is heated. 257,070 4/1882 Rhodes ..43l/74 3,323,019 f 2 Claims, 1 Drawing Figure IGNITION DEVICE FOR A GAS FIRED APPLIANCE BACKGROUND OF THE INVENTION In many gas fired applicances-utilizing a pilot flame for igniting the main appliance burners, it is desirable to provide for automatic reignition of the pilot flame in the event of pilot outage. This is especially true when the gas fired appliance'is installed in a relatively inaccessible location, suchas a roof top. A spark generation device may be utilized for reigniting the pilot flame. However, to prolong the life of the contacts in the spark generator, numerous devices such as flame sensors have heretofore been employed to deactivate the spark generation device once a flame has been established; The flame sensors and associated hardware increase both the cost and complexity while decreasing the reliability of the spark generation device.

SUMMARY OF THE INVENTION This invention relates to a spark generator for ignition of combustible gases including an electric coil having a core associated therewith. A set of contacts adapted for connection'to a source of electrical energy is operatively associated with'the electric coil and core of an electromagnet, one-contact of said contact set BRIEF DESCRIPTION OF THE DRAWING The drawing is a view partially in section, partially schematic of a controlsystem for a gas fired appliance.

DESCRIPTION OF THE PREFERRED 1 EMBODIMENT Referring to the drawing, there is illustrated a combination gas valve 3 having an inlet 5 and an outlet 7. The combination gas valve includes a manual shut-off valve adapted to completely block the flow of gas to the main burners and the pilot burners when in the off position, to provide gas only to the pilot burner when in the pilot position, and to allow flow of gas to the pilot burner and themain burner when in the on position. A second electrically actuated valve may be provided within combination gas valve 3 downstream from the manual valve to allow remote control of the main burners by suitable thermostatic'control means 8.'The

. thermostatiecontrol'means 8 isv connectedin series with the electrically actuated valve portion of the combination gas valve3 and the low voltage side of a suitable transformer 10. Safety devices such as an overtemperature switch 12 may also be connected in series with the electrically actuated gas valve to deenergize the valve and shut off the main burner in the event of a malfunction.

. A pilot gas line 9 provides gas from thecombination valve to the pilot assembly II. A pressure switch 13 in the pilot gas line 9 having normally open contacts therein is electrically connected to a spark generating device 15 disposed adjacent the pilot burner for igniting the pilot in a manner to be hereinafter explained.

The spark generating device 15 includes a sub-frame 17 mounted on a main frame 19 and electrically isolated therefrom by a suitable insulator 21. The subframe 17 is attached to the main frame 19 by means of a rivet 23 which is spaced from subframe 17 and main frame 19 by suitable insulating washers 25. A core 27 having an electrical coil 29 thereon is mounted on subframe 17. An armature 31 which is of bimetallic construction to render it operative as a thermostat is also connected to subframe 17 by suitable means such as rivet 33. A contact set, including a first'contact 35 mounted on bimetallic armature 31, and a second contact 37 mounted on frame 19 is provided for generating a spark therebetween. The pressure switch 13 and spark generating device 15 are electrically connected in series to the low voltage terminals of the transformer 10.

Considering the operation of the control system, when the manual gas valve is turned on and pilot flame is out, pressure in pilot line 9 will'cause pressure switch 13 to close and provide current to spark generating device 15. Current flow from switch 13 through line 14, frame 19, contact 37, contact 35, armature 31, subframe 17, and coil 29 will complete a circuit through the transformer. Current flow through coil 29 will cause the armature 31 to be drawn. toward core 27, thereby opening contacts 35 and 37. Opening of con tacts 35 and 37 will deenergize coil 29 allowing armature 31 to move away from core 27 and close contacts 35, 37. The resulting rapid opening and closing of con tacts 35 and 37 will cause sparks to be generated therebetween for igniting the gas issuing from the pilot burner assembly 11. Upon ignition of the pilot burner, heat from the burner will be radiated to bimetallic armature 31 causing the armature to warp in a direction to open contacts 35 and 37 and prevent further sparking to prolong the life of the contacts. In the event the pilot flame does not light, heat produced by the spark generation and resistive heating produced by the current flow through armature 31 will cause the armature to warp and open the contacts after a predetermined period of operation. When the armature has cooled sufficiently, the contacts will again close and the spark generator will again operate for a period of time in an attempt to light the pilot.

Once the pilot is lit, armature 31, as stated heretofore, will be heated sufficiently to hold the contacts 35 and 37 open. In the event that the pilot flame is extinguished, the armature will cool, thereby allowing the contacts to close and again actuate the spark generating device to relight the pilot. When the manual valve on the combination gas valve 3 is moved to the off position, the pressure switch 13 will open and prevent operation of the spark generating device.

It can be seen from the foregoing that the spark generating device is automatically energized whenever gas is supplied to the pilot burner and the pilot flame is extinguished. The spark generating device will automatically be deenergized once the pilot flame is established.

While I have described a preferred embodiment of my invention, it is to be understood this invention is not limited thereto but may be otherwise embodied within the scope of the following claims.

I claim:

1. A device for generating sparks to ignite and main- 4 tain the ignition of a combustible gas, said device comprising:

a source of electrical energy;

mountingmeans;

a set of electrical contacts secured to said mounting means and energizable by said electrical source, said contacts being separable from a normal closed position of contact and being adapted to generate gas igniting sparks when energized and separated by a limited distance;

electromagnetic means energizable by said electrical source for alternately effecting the separation and closing of said contacts tocause spark generation; said electromagnetic means comprising a bimetallic thermostatic armature carrying one of said contacts, an electromagnet secured to said mounting means and carrying an electric coil, said electric coil being connected in series with the electrical contacts and the electrical source, said armature being biasedtowards a first position in which said contacts are closed and being movable fromthe first position in response to the energization of said electromagnet by said electric coil to-open said tric switch means for connecting said electromagnetic means to said source of electrical energy comprises a pressure sensitive switch operated by the gas pressure and adapted to connect said electromagnetic means to said source in response to a gas pressure characteristic of non-ignition of the gas. 

1. A device for generating sparks to ignite and maintain the ignition of a combustible gas, said device comprising: a source of electrical energy; mounting means; a set of electrical contacts secured to said mounting means and energizable by said electrical source, said contacts are separable from a normal closed position of contact and being adapted to generate gas igniting sparks when energized and separated by a lImited distance; electromagnetic means energizable by said electrical source for alternately effecting the separation and closing of said contacts to cause spark generation; said electromagnetic means comprising a bimetallic thermostatic armature carrying one of said contacts, an electromagnet secured to said mounting means and carrying an electric coil, said electric coil being connected in series with the electrical contacts and the electrical source, said armature being biased towards a first position in which said contacts are closed and being movable from the first position in response to the energization of said electromagnet by said electric coil to open said contacts to effect the generation of sparks, and said armature being deformable in response to a temperature determined according to the ignition temperature of the gas to separate said contacts sufficiently to prevent spark generation; and electric switch means for connecting said electromagnetic means to said source of electrical energy in response to the nonignition of the gas; whereby said set of contacts are operable to generate sparks so long as the gas is not ignited.
 2. A device according to claim 1 wherein said electric switch means for connecting said electromagnetic means to said source of electrical energy comprises a pressure sensitive switch operated by the gas pressure and adapted to connect said electromagnetic means to said source in response to a gas pressure characteristic of non-ignition of the gas. 